Fractional flow reserve (FFR) is an important technique for diagnosis of coronary function. FFR is defined as a ratio of the pressure distal to a stenosis relative to the pressure proximal to the stenosis during the maximal coronary blood flow (hyperemia) so as to reflect how the stenosis limits the maximum blood flow and can serve as a criterion for determining whether it will induce ischemia. A large number of clinical trials so far have provided adequate evidences indicating that FFR can be used to assess the functional significance of a stenotic lesion and in particular can provide important guidelines in the treatment plan selection for a critical stenotic lesion.
Invasive measurement of a blood pressure by means of pressure wire involves a significant amount of work and is associated with a risk of damaging the vessel. Patent Application No. CN201510901329.X, filed on Dec. 8, 2015, entitled “Method and System for Calculating Blood Vessel Pressure Difference and Fractional Flow Reserve (FFR)” discloses obtaining a pressure deviation within a blood vessel with lesions of different degrees of severity through computation in multiple scales based on a geometrical parameter and a blood flow velocity of the vessel obtained by coronary angiography. It is capable of properly distinguishing and evaluating the different impacts of geometric changes of a stenosed vessel with different degrees of severity on the blood flow pressure.
For a blood vessel with multiple degrees of stenosis, the location(s), size(s), number(s) and implantation order of stent(s) that is/are to be implanted are all of clinical interest. At present, no method has been developed for fast real-time prediction of the impact of stent implantation on FFR, which is, however, of great clinical significance.
To overcome the above problems, the inventors of the present invention, based on their previous work, i.e., Patent Application entitled “Method and System for Calculating Blood Vessel Pressure Difference and Fractional Flow Reserve (FFR)”, as well as further inventive effort and improvement efforts, realized computation and assessment of a pressure drop and FFR within a virtually-stented blood vessel with lesions of different degrees of severity, which can help clinicians in the selection of a stenting strategy and assessment in prognosis.